More on Pheromones

Pheromones in Humans: Research and Studies
Lately, many researchers are interested in discovering pheromones in humans. Many are convinced that humans also emit pheromones that govern behavior (Carlson, 2005, p. 272). One study conducted by Russell, Switz, and Thompson (1980) collected sweat from the armpits of one female donor, mixed with alcohol, and swabbed under the noses of other participants. The results showed that the rest of the female participants’ menstrual cycle gradually synchronized with the female sweat donor of which the sweat sample was taken from (Carlson, 2005, p. 273).
Another similar study conducted by McClintock (1971) discovered an occurrence similar to that of the Whitten effect found in mice. She found women with close relationships and who spend many hours together tended to have synchronized cycles. Also, it was discovered that women who spent time with men tended to have shorter cycles. Those who spent less time with the opposite sex tended to have longer cycles (Carlson, 2005, p. 273). McClintock later teamed up with another researcher by the name of Stern and elaborated on this experiment. Here, they had nine women donate sweat from their underarm pits for 8 hours a day. Twenty women then received the combination of sweat and isopropyl alcohol. This mixture was dabbed under their noses. The results found that the receiving women’s cycle either sped up or slowed down. Specifically, women who received the pheromone during pre-ovulation had shorter monthly cycles by approximately two days. The women whose ovulations were occurring during the experiment had delayed cycles as much as one day and a half. A controlled group was also utilized on this study. This control group did not receive any pheromones. They had no changes in their cycle. It was also noted in this study that nasal congestion in participants hampered the effects of the pheromone (Seppa, 1998).
Pheromone Physiology
All three experiments utilize the olfactory organ in the detection of pheromones. However, contrary to what one would assume, the primary olfactory system is not responsible for pheromone stimulus processing. Instead, processing lies in an organ called the vomeronasal organ (VNO). The vomeronasal organ is a group of sensory receptors at the base of a duct leading into the nasal passages (Carlson, 2005, 270). . This organ is sensitive to “nonvolatile compounds found in urine or other substances” (Carlson, 2005, 272). It is found in most mammals with the exception of dolphins and whales. In humans, the presence of this organ is a controversial issue. There are scientists, however, that believe that the human vemeronasal organ is located near the bottom of the septal wall that divides the nose (Woronczuk, Medwid, Neumann, and Eshelman, 1999). This theory was tested by inserting a specially designed electrode into the VNO. When inserted into the olfactory cleft and exposed to pheromones, no changes were found. Yet, when placed in the VNO, neurons were recorded to be responding. It should also be noted that hormone levels in the blood also changed. It is believed that the VNO sends information to the brain’s hypothalamus which is responsible for bodily functions such as mating. It is also possible that the VNO communicates with the limbic system---the part of the brain responsible for emotional responses (Woronczuk et al., 1999).
The presence of the vemeronasal organ in humans would explain why nasal congestion hampered the effects of pheromones in the McClintock and Stern experiment
Perhaps pheromones can be better related and illustrated through the occurrence related to hysterectomy. Many women who have undergone this surgery report lack of sexual urges following the procedure. In an article by Michael D. Lemonick (2004, February), Lemonick features a woman by the name of Roslyn Washington. Ms. Washington claims that the hysterectomy procedure left her with side effects she wasn’t prepared for. Among these were a decrease in sexual activity, lack of sexual desire, and failure to become stimulated from glances, looks, and touches from the opposite sex. When Ms. Washington opted to receive transdermal testosterone, she was once again able to feel “stimulated” (Lemonick, 2004). When the testosterone treatment was stopped, her desire began to once again decrease. This perhaps indicates that pheromones are responsible for sexual desire and is necessary to trigger sexual responses.
Evolutionary Perspective
It seems that pheromones related to sexual behavior is tied closely to attractiveness and mate selection. It has been suggested that the scent of the human body is a signal of “phenotypic and genetic quality” (Thornhill & Gangestad, 1999). According to an article by Thronhill and Gangestad (1999, March) women who were at their higher period of fertility during ovulation found that the scents of men who have greater body bilateral symmetry more attractive. On the other hand, women in low fertility phases or those who are on hormone based contraceptive do not show this preference. Other studies found that men did not prefer the scent of symmetrical women. These perhaps suggest that women have a more evolved preference to mate and reproduce with men who posses good genes.
It is proposed that symmetry equates good and healthy genes which in turn produce offspring who are not only healthy and developmentally sound but one that can survive into adulthood (Carey, 2006). Evolutionary theorists would probably tie this in with the parental investment theory. This theory suggests that women are pickier in mate selection due to the fact that their minimum investment in childbearing involves 9 months plus the physical traumatic experience of childbirth. It can be said that women value sires with good genes because they seek to minimize the number of their offspring because their investment is so much greater (Boyd & Bee, 2006, p. 90). In contrast, this theory proposes that men value availability. They are less selective on their partners because their minimum investment in parenting only required a single act of sexual intercourse. It can also be pointed out that “men seek to maximize the likelihood of the survival species by maximizing the number of their offspring” (Boyd & Bee, 2006, 90). Thus, this would explain why men did not prefer the scent of symmetrical women in the experiment conducted by Thronhill and Gangestad.
Genetic Standpoint
Researchers have been found that women preferred male odors belonging to men who were genetically different from their own. Swiss zoologist, Claus Wedekind, conducted an experiment using 49 women and 44 men with a variety of MHC genes (PBS, 2001). MHC stands for major histocompatibility locus. These are “genes code for special protein markers that are attached to the surface of cells and help the body recognize whether a cell belongs to an organism or if it is an invader such as a bacteria or virus” (Woronczuk et al., 1999).
In this experiment the male participants were asked to wear T-shirts to wear for two nights. These t-shirts were then placed in a box armed with a “smelling hole” (PBS, 2001). The female participants were then invited to sniff the boxes and rate the odors according to “intensity, pleasantness, and sexiness” (PBS, 1999). Results showed that women were attracted to the smells belonging to men who were MHC different from themselves. It then can be concluded that an individual would be attracted most to a person who is genetic immunity to disease differs most from our own thus producing stronger, healthier children (PBS, 1999).
Interestingly, in another similar study conducted by Richardson (1996), it was found that women with similar MHC genes with specific males would be reminded of her brother or father. On the other hand, dissimilar MHC genes would remind her of a past or current boyfriend (Woronczuk et al., 1999). Another interesting finding of this research is on how this had an opposite effect on women who were using birth control pills. The article proposes that the birth control pill probably “trick[s] the body into thinking its pregnant, and women on the pill often report that they prefer smells that remind them of home and relatives” (Woronczuk et al., 1999).
(Hmmm....disturbing.....).
Anyway.....
Research on human pheromones is yielding intriguing results. Furthermore, it seems that human pheromones offer promising implications and uses in bettering female health and understanding attraction. So far, the author can see a variety of benefits pheromones knowledge can bring to human kind. This includes: menstrual regulation for those with irregular periods, fertility and conception problems, genetic disease prevention, and marital/couple therapy. Indeed, with the continued study of this relatively new concept applied to humans, the possibility of its uses and benefits to human kind are endless.

References
Carey, B. (2006, Feb.). The rules of attraction in the game of love. Retrieved May 29, 2010.
from http://www.livescience.com/health/060213_attraction_rules.html.
Carlson, N.R. (2005). Foundations of physiological psychology (6th ed.). Boston: Pearson
Education, Inc.
Lemonick, M.D. (2004, February). The chemistry of desire. Time, 163(6), 50-55. Retrieved

May 18, 2010, from CBCA Complete. (Document ID: 557070811).

PBS. (1999). Sweaty t-shirts and human mate choice. Retrieved May 29, 2010. from

http://www.pbs.org/wgbh/evolution/library/01/6/l_016_08.html

Seppa, N. (1998, March). Nailing down pheromones in humans. Science
News, 153(11), 164. Retrieved May 16, 2010, from Research Library. (Document
ID: 27464966).
Thornhill, R. & Gangestad, S.W. (1999, March). The scent of symmetry: A human sex
pheromone that signals fitness? Retrieved May 18, 2010.
Woronczuk, J., Medwid, S., Neumann, L., and Eshelman, S. (1999). Are there human
pheromones? Retrieved May 29, 2010. from
http://www.macalester.edu/psychology/whathap/ubnrp/smell/attraction.html

Fear and Pheromones

Pheromones are used for communication within a species. When an organism releases pheromones, it elicits either an overt or physiological reaction in the receiving organism of the same species (Carlson, 2007, p. 271). Pheromones were originally studied in insects. For instance, it was found that when ants rub their antennas together they are exchanging pheromones to confirm each other’s species and colony identity (Seppa, 1998). Later studies extended to smaller animals such as mice ( as previously discussed in Physiology and reproduction as posted on 1/10/10. e.i Lee-Boot effect and Whitten effect).
Research and interest on human pheromones is relatively new concentrating mainly on sexuality and attraction. It was interesting to find another angle of study on this interesting subject.
Apparantly, it has been discovered that there is a pheromone for fear. An article in The Pretonia News (2008) cited a research study that investigates whether sweat can give out signals that might subconsciously be picked up by others. US researchers collected sweat from 40 novice sky divers as they fell of to the earth by taping absorbant pads to their armpits. A second group of of volunteers were asked to smell the samples while having their brain scanned. It revealed increased activity in the areas of the brain associated with fear and emotional responses---the amygdala and hypothalamus (The Pretonia News, 2008).
The potential of the fear pheromone apparantly has peaked the interest of many scientist and researchers. At this time, the City University of London with the support of The Home Office Scientific Development Branch is developing the technology to produce two sensors that can "detect the unique chemical signiture of the fear pheromone" (Zolfagharifard, 2009). These devices will be specifically designed to identify terrorist at airport security checks and high profile events.This technology is foreseen to be developed within the next two to three years (Evening Chronicle, 2009).
There have also been reports of isolating the fear pheromone for warfare purposes. An article by Randerson (2008) cites the US Defense Advanced Research Projects Agency, otherwise known as "DARPA" as one oganizational group funding this type of study. He further speculates the possibility of its use in inducing terror in enemy troops. DARPA, of course, denies that they will further fund any more research of this field or that it plans to use fear pheromones for military purposes.

References
James Randerson. (2008, December 5). You can smell fear, say scientists. The Hindu,***[insert pages]***. Retrieved June 4, 2010, from ProQuest Newsstand. (Document ID: 1808742081).
Ellie Zolfagharifard. (2009, October). NEWS: Sensor system sniffs out trouble. The Engineer,12. Retrieved June 4, 2010, from ABI/INFORM Global. (Document ID: 1886558551).
Carlson, N.R. (2005). Foundations of physiological psychology (6th ed.). Boston: Pearson Education, Inc.
Scientists sniff out 'fear sweat' :NWS. (2008, December 8). The Pretoria News,6. Retrieved June 4, 2010, from ProQuest Newsstand. (Document ID: 1608424461).
A DEVICE that smells human [ ... ]. (2009, November 9). Evening Chronicle,4. Retrieved June 5, 2010, from ProQuest Newsstand. (Document ID: 1897025011).